Conventionally, in a fluid pressure operation machine such as a tractor, a fluid pressure control device is used that uses a working fluid discharged from a fluid pressure pump to drive an actuator.
JP08-261206A discloses a hydraulic control device that controls the ascent and descent of the lift cylinder of a farm tractor. This hydraulic control device includes an ascent valve that is provided between a hydraulic pump and the lift cylinder and that is controlled by an adjustment value, a descent proportional solenoid valve that is provided between the lift cylinder and a tank, and a check valve which is provided between the lift cylinder and the descent proportional solenoid valve and in which the opening and closing thereof is controlled by a pilot valve.